A Soft Stretch-flexible Pressure Sensor for Tactile Sensing on Nonplanar Surfaces

Pressure sensors are indispensable in wearable equipment, human-machine interfaces, and robotics. However, facile and rapid fabrication of stretch-flexible pressure sensors with good performance is still needed. In this paper, a fast-response pressure sensor used for tactile sensing on a nonplanar surface was prototyped in an effortless manner on the basis of laser-induced graphene (LIG) and a sugar-Template porous Ecoflex dielectric layer. The intrinsic correlation among the structure size, material properties, sensor sensitivity and response time is revealed. The results show that the pressure sensor achieves a sensitivity of 0.04 kPa-1 with an accuracy of 3.1% within 35 kPa when the dielectric thickness is 1 mm and the LIG electrode scribing power and speed were set as 2.1 W and 70 mm/s, respectively. The limit of detection is 5.3 g, corresponding to a pressure level of 132 Pa. The response and recovery time of the pressure sensor were also characterized as 70 and 80 ms, respectively. In addition, a 3 3 stretch-flexible sensor array is fabricated and attached to a nonplanar surface for single and multitouch tactile sensing. The highly integrated pressure sensor is cost-effective, highly scalable, and fast response, which offers a significant opportunity for the next generation of tactile sensors on nonplanar surfaces for robots.